According to court documents, the families of the patient, Mary Bartlett, who was being transported and flight nurse Kristopher Harrison filed lawsuits after the Eurocopter MBB-BK went down in Perquimans County.
Read Bartlett's and Harrison's full complaints
The crash also killed the pilot, Jeffrey Burke, and flight nurse, Crystal Sollinger.
READ MORE: 4 dead in Duke Life Flight helicopter crash in eastern NC
The suit claims the cause of the crash was because of engine failure and believe that it could have been prevented.
CLICK HERE TO READ THE COURT DOCUMENTS (.pdf)
Documents also state that the accident followed a similar crash involving the same engine problem on the same model helicopter just eight months earlier.
"All evidence points to a blocked engine drain line," said aviation attorney representing the families, Gary C. Robb. "That blockage will lead to an engine fire and then complete shutdown of that engine ... This was absolutely a preventable crash. The engine and aircraft manufacturers knew at least since January 2017 (when the earlier crash took place) how extremely dangerous this potential engine fire and failure situation was. Yet, they sat on their hands and did nothing."
The lawsuits name the manufacturer of the engine, Safran Helicopter Engines, a French corporation; its U.S. distributor, Safran USA, Inc.; the helicopter manufacturer, Airbus Helicopters Deutschland GmbH, a German entity; and its U.S. distributor, Airbus Helicopters, Inc.
"The Federal Aviation Administration, in November took it upon themselves to send out ... called a special air awareness information bulletin advising owners and operators of this helicopter with those engines to check the engine drain line, to make certain that it's clear," Robb told ABC11 Tuesday. "And if that had been done before September of this year, in a reasonably timely fashion, it is our submission that this crash would never have occurred."
The families claim that the pilot also was at fault for causing the crash for failure to perform proper emergency procedures when the engine failed.
The lawsuits claim unspecified compensatory and punitive damages.